import model
from sqlalchemy.orm import mapper,relationship
from sqlalchemy import MetaData,Table,Column,Integer,String
metadata = MetaData()
order_lines = Table(
    "order_lines",
    metadata,
    Column("id",Integer,primary_key=True,autoincrement=True),
    Column("sku",String(255)),
    Column("qty",Integer,nullable=False),
    Column("orderid",String(255),)
)

def start_mappers():
    lines_mapper = mapper(model.OrderLine,order_lines)